We propose a novel class of atomic clocks based on highly charged ions. We consider highly forbidden laser-accessible transitions within the $4f^{12}$ ground-state configurations of highly charged ions. Our evaluation of systematic effects demonstrates that these transitions may be used for building exceptionally accurate atomic clocks which may compete in accuracy with recently proposed nuclear clocks.

We consider slowly rotating, stationary, axisymmetric black holes in the infrared limit of Hořava-Lifshitz gravity. We show that such solutions do not exist, provided that they are regular everywhere apart from the central singularity. This has profound implications for the viability of the theory, considering the astrophysical evidence for the existence of black holes with nonzero spin.

We present an embedding of the three-dimensional relativistic Landau-Ginzburg model for condensed matter systems in an $\mathcal{N}=6$, $U(N)\times U(N)$ Chern-Simons-matter theory [the Aharony-Bergman-Jafferis-Maldacena model] by consistently truncating the latter to an Abelian effective field theory encoding the collective dynamics of $\mathcal{O}(N)$ of the $\mathcal{O}(N^2)$ modes. In fact, depending on the vacuum expectation value on one of the Aharony-Bergman-Jafferis-Maldacena scalars, a mass deformation parameter $\mu$ and the Chern-Simons level number $k$, our Abelianization prescription allows us to interpolate between the Abelian Higgs model with its usual multivortex solutions and a ${\varphi }^4$ theory. We sketch a simple condensed matter model that reproduces all the salient features of the Abelianization. In this context, the Abelianization can be interpreted as giving a dimensional reduction from four dimensions.

Isospin-dependent nuclear forces play a fundamental role in nuclear structure. In relativistic models of nuclear structure constructed at the quark level these isovector nuclear forces affect the $u$ and $d$ quarks differently, leading to nontrivial flavor-dependent modifications of the nuclear parton distributions. We explore the effect of isospin dependent forces for parity-violating deep inelastic scattering on nuclear targets and demonstrate that the cross sections for nuclei with $N\ne Z$ are sensitive to the flavor dependence of the EMC effect. Indeed, for nuclei like lead and gold we find that these flavor-dependent effects are large.

We demonstrate rotational and vibrational cooling of cesium dimers by optical pumping techniques. We use two laser sources exciting all the populated rovibrational states, except a target state that thus behaves like a dark state where molecules pile up thanks to absorption-spontaneous emission cycles. We are able to accumulate photoassociated cold ${\mathrm{Cs}}_2$ molecules in their absolute ground state ($v=0$, $J=0$) with up to 40% efficiency. Given its simplicity, the method could be extended to other molecules and molecular beams. It also opens up general perspectives in laser cooling the external degrees of freedom of molecules.

The influence of quantum effects on the processes of initiation of combustion and detonation of hydrogen and acetylene near the low-temperature limits at elevated pressures is analyzed. A theoretical consideration which allows quantification of the quantum corrections to the rate constants of endothermic reactions associated with an increase in the high-energy tail of the equilibrium momentum distribution function at high pressures is presented. This quantum effect is caused by a manifestation of the principle of uncertainty for the energy of the colliding particles at a high frequency of collisions. It is shown that significant deviations of experimentally observed ignition and detonation delay time from the predictions of kinetic calculations are quite well described by the proposed quantum corrections. This general mechanism should be considered in the safety problem with emergency emissions of hydrogen at nuclear power stations, as well as problems of the safe production and storage of hydrogen and acetylene, which have a fundamental importance for industry and power engineering.

A theory of correlations between $N$ photons of given frequencies and detected at given time delays is presented. These correlation functions are usually too cumbersome to be computed explicitly. We show that they are obtained exactly through intensity correlations between two-level sensors in the limit of their vanishing coupling to the system. This allows the computation of correlation functions hitherto unreachable. The uncertainties in time and frequency of the detection, which are necessary variables to describe the system, are intrinsic to the theory. We illustrate the power of our formalism with the example of the Jaynes-Cummings model, by showing how higher order photon correlations can bring new insights into the dynamics of open quantum systems.

We demonstrate quantum bath engineering for a superconducting artificial atom coupled to a microwave cavity. By tailoring the spectrum of microwave photon shot noise in the cavity, we create a dissipative environment that autonomously relaxes the atom to an arbitrarily specified coherent superposition of the ground and excited states. In the presence of background thermal excitations, this mechanism increases state purity and effectively cools the dressed atom state to a low temperature.

Using a superconducting circuit, the Josephson mixer, we demonstrate the first experimental realization of spatially separated two-mode squeezed states of microwave light. Driven by a pump tone, a first Josephson mixer generates, out of quantum vacuum, a pair of entangled fields at different frequencies on separate transmission lines. A second mixer, driven by a $\pi$-phase shifted copy of the first pump tone, recombines and disentangles the two fields. The resulting output noise level is measured to be lower than for the vacuum state at the input of the second mixer, an unambiguous proof of entanglement. Moreover, the output noise level provides a direct, quantitative measure of entanglement, leading here to the demonstration of $6\mathrm{Mebit}·{\mathrm{s}}^{-1}$ (mega entangled bits per second) generated by the first mixer.

We observe off-axis phase-matched terahertz generation in long air-plasma filaments produced by femtosecond two-color laser focusing. Here, phase matching naturally occurs due to off-axis constructive interference between locally generated terahertz waves, and this determines the far-field terahertz radiation profiles and yields. For a filament longer than the characteristic two-color dephasing length, it emits conical terahertz radiation in the off-axis direction, peaked at $4–7°$ depending on the radiation frequencies. The total terahertz yield continuously increases with the filament length, well beyond the dephasing length. The phase-matching condition observed here provides a simple method for scalable terahertz generation in elongated plasmas.

We predict the splitting of a high-order optical vortex into a constellation of unit vortices, upon total internal reflection of the carrier beam, and analyze the splitting. The reflected vortex constellation generalizes, in a local sense, the familiar longitudinal Goos-Hänchen and transverse Imbert-Fedorov shifts of the centroid of a reflected optical beam. The centroid shift is related to the center of the constellation, whose geometry otherwise depends on higher-order terms in an expansion of the reflection matrix. We derive an approximation of the amplitude around the constellation as a complex analytic polynomial, whose roots are the vortices. Increasing the order of the initial vortex gives an Appell sequence of complex polynomials, which we explain by an analogy with the theory of optical aberration.

A method is presented for determining the dynamic contact angle at the three-phase contact between a solid, a liquid, and a vapor under an applied force, using molecular simulation. The method is demonstrated using a Lennard-Jones fluid in contact with a cylindrical shell of the fcc Lennard-Jones solid. Advancing and receding contact angles and the contact angle hysteresis are reported for the first time by this approach. The increase in force required to wet fully an array of solid cylinders (robustness) with decreasing separation distance between cylinders is evaluated. The dynamic contact angle is characterized by partial slipping of the three phase contact line when a force is applied.

We report the first direct measurement of the emission duration of laser-accelerated fast electrons from the surface of a solid target irradiated by a high-intensity femtosecond laser pulse. The emission duration is determined by autocorrelation measurement using the Coulomb repulsive forces that act on two equivalent electron pulses. The emission duration depends on the laser pulse duration for laser pulses of 200–690 fs. Numerical modeling of three-dimensional charged particle dynamics indicates that the emission duration of fast electrons is almost equal to the duration of the laser pulse.

Profound temperature peaks are observed in regions of high velocity shear in a 2D dusty plasma experiment with laser-driven flow. These are attributed to viscous heating, which occurs due to collisional scattering in a shear flow. Using measurements of viscosity, thermal conductivity, and spatial profiles of flow velocity and temperature, we determine three dimensionless numbers: Brinkman, $\mathrm{Br}=0.5$; Prandtl, $\mathrm{Pr}=0.09$; and Eckert, $\mathrm{Ec}=5.7$. The large value of Br indicates significant viscous heating that is consistent with the observed temperature peaks.

Scaling laws for the transport and heating of trace heavy ions in low-frequency magnetized plasma turbulence are derived and compared with direct numerical simulations. The predicted dependences of turbulent fluxes and heating on ion charge and mass number are found to agree with numerical results for both stationary and differentially rotating plasmas. Heavy ion momentum transport is found to increase with mass, and heavy ions are found to be preferentially heated, implying a mass-dependent ion temperature for very weakly collisional plasmas and for partially ionized heavy ions in strongly rotating plasmas.

Ferroelectric cathodes were reported as a feasible electron source for microwave tubes. However, due to the surface plasma emission characterizing this cathode, operation of millimeter wave tubes based on it remains questionable. Nevertheless, the interest in compact high power sources of millimeter waves and specifically 95 GHz is continually growing. In this experiment, a ferroelectric cathode is used as an electron source for a gyrotron with the output frequency extended up to 95 GHz. Power above a 5 kW peak and $\sim 0.5\mu \mathrm{s}$ pulses are reported; a duty cycle of $10\%$ is estimated to be achievable.

Phase transitions are not usually seen in the time domain. Here, we report on the finding of critical times at which a physical observable, in the thermodynamic limit, becomes nonanalytic as a function of time. We find that the coherence of a probe spin coupled to a many-body system vanishes at times in one-to-one correspondence to the Lee-Yang zeros of the partition function of the many-body system. In the thermodynamic limit, the Lee-Yang zeros form a continuum cut in the complex plane of fugacity and the probe spin coherence presents sudden death and birth at the critical times corresponding to the Yang-Lee singularities. These results provide new experimental possibilities in many-body physics.

Recent studies of Cu-Zr glasses have reported a rapid variation in the amorphous phase density near the optimal glass forming compositions, supporting the belief that the densest liquids are also the best glass formers. Here, we show that the measured densities of the Cu-Zr liquids at higher temperatures are not peaked sharply near these compositions, but the volume expansivities are. Theoretical studies have shown that the expansivity correlates with fragility near $T_g$; the experimental results presented here show that at high temperature they become anticorrelated. From energy landscape arguments, this indicates the existence of a crossover temperature for the expansivity-fragility correlation that scales inversely with the liquid fragility. These results lead to an improved understanding of the high temperature properties of liquids that form glasses and suggest a new method for identifying the best glass forming compositions within an alloy system from the properties of the equilibrium liquids.

We present a study of the entanglement in the electronic structure of the late transition metal monoxides—MnO, FeO, CoO, and NiO—obtained by means of density-functional theory in the local density approximation combined with dynamical mean-field theory. The impurity problem is solved through exact diagonalization, which grants full access to the thermally mixed many-body ground state density operator. The quality of the electronic structure is affirmed through a direct comparison between the calculated electronic excitation spectrum and photoemission experiments. Our treatment allows for a quantitative investigation of the entanglement in the electronic structure. Two main sources of entanglement are explicitly resolved through the use of a fidelity based geometrical entanglement measure, and additional information is gained from a complementary entropic entanglement measure. We show that the interplay of crystal field effects and Coulomb interaction causes the entanglement in CoO to take a particularly intricate form.

We report a globally reversible effect of electronic tuning on the magnetic phase diagram in ${\mathrm{CeCoIn}}_5$ driven by electron (Pt and Sn) and hole (Cd, Hg) doping. Consequently, we are able to extract the superconducting pair breaking component for hole and electron dopants with pressure and codoping studies, respectively. We find that these nominally nonmagnetic dopants have a remarkably weak pair breaking effect for a $d$-wave superconductor. The pair breaking is weaker for hole dopants, which induce magnetic moments, than for electron dopants. Furthermore, both Pt and Sn doping have a similar effect on superconductivity despite being on different dopant sites, arguing against the notion that superconductivity lives predominantly in the ${\mathrm{CeIn}}_3$ planes of these materials. In addition, we shed qualitative understanding on the doping dependence with density functional theory calculations.